Page 51 - Freshwater-Biology-and-Ecology-Handbook

Table 1.6
System A and B for typology of rivers (from WFD)

System A System B In practice, these typologies
were not widely used to
Ecoregion Shown on map Obligatory Altitude define reference values.
Altitude >800 m Latitude This is because different
environmental parameters
200–800 m Longitude determine the distribution
<200 m Geology of different biological
Size of 10–100 km2 Size quality elements and
catchment therefore the reference
area 100–1000 km2 Optional Distance from river source values of metrics used to
1000–10,000 km2 Energy flow measure biological quality.
>10,000 km2 Mean water width
For example, the reference
Geology Calcareous Mean water depth values for the UK’s diatom
Siliceous Mean water slope classification are based
only on alkalinity, whereas
Organic Form and shape of main river bed
the reference values for
River discharge category river invertebrates are
Valley shape based on twelve different
parameters. In this
Transport of solids
handbook, the prediction
Acid neutralising capacity of reference values for each
Mean substratum composition quality element is described
in the section relating to
Chloride
that element.
Air temperature range
Mean air temperature The UK’s national typology
was used only for reporting
Precipitation
monitoring results to the
Table 1.7 European Commission.
System A and B for typology of lakes (from WFD)

System A System B

Ecoregion Shown on map Obligatory Altitude
Altitude >800 m Latitude
200–800 m Longitude
<200 m Depth
Mean depth <3 m Geology
3–15 m Size
>15 m Optional Mean water depth
Surface area 0.5–1 km 2 Lake shape
1–10 km 2 Residence time
10–100 km 2 Mean air temperature
>100 km 2 Air temperature range
Geology Calcareous Mixing characteristics
Siliceous Acid neutralising capacity
Organic Background nutrient status
Mean substratum composition
Water level fluctuation

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